Effects of Calcium Ions on Anionic Polyacrylamide Fouling of Ion-Exchange Membranes in Polymer-Flooding Wastewater Treatment by Electrodialysis
The effects of calcium ions (Ca2+) on anionic polyacrylamide (APAM) fouling of ion-exchange membranes (IEMs) in polymer-flooding wastewater (PFW) treatment by electrodialysis were systematically investigated by associating the desalination performance and physicochemical and electrochemical characteristics with the electrostatic interaction and interfacial free energy. In this study, bench-scale experiments were performed on homogeneous and heterogeneous IEMs to investigate the fouling mechanisms with different molecular weights (MWs). It was found that APAM fouling mainly occurred on the anion-exchange membranes (AEMs) due to electrostatic attraction, which significantly deteriorated the membrane desalination performance. Under the same experimental conditions, the membrane fouling of APAM with a MW of 6 million Dalton (600APAM) was more serious than that of 0.5 million Dalton (50APAM), and APAM fouling on homogeneous membranes was more serious than that on heterogeneous membranes. Ca2+ would connect with the carboxylate ions of APAM by coordination. The electrostatic attraction between APAM molecules and AEM weakened due to increasing zeta potential after CaCl2 addition. And as a result, the APAM+Ca fouling formed intricate and compact aggregates sparsely distributed on the surface of AEMs compared to the APAM fouling layer. Both electrostatic interactions and interfacial free energy affected APAM fouling of IEMs, but electrostatic interactions dominated
Year of publication: |
[2022]
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Authors: | Xia, Qing ; Zhou, Zhen ; Zhao, Xiaodan ; Zhang, Maonan ; Wu, Chunhua ; Yu, Shuili ; Liu, Guicai |
Publisher: |
[S.l.] : SSRN |
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